Blocked nose and headache

I was researching links between CPAP usage and headaches and I found here https://www.cpap.com/cpap-faq/Common-Side-Effects.html that it could be due to blocked up sinuses.
So I was wondering if anyone else had this issue and solved it, maybe with one of those nose sprays? or should I get a FFM?

I do have a lightly deviated septum and one of my nostrils will be blocked when I go to bed.

Google "cpap rhinitis"
I think once you get your humidifier and use it that your congestion issues will improve substantially.

When the nasal mucosa get dried out they respond by swelling just like they do with a common cold or allergy attack.
Nasal sprays like Afrin help reduce the swelling chemically but the problem with using them very much is the nasal mucosa get to where they only reduce the swelling in response to the chemical and then we need more and more of the chemical to get the same job done. Short term use...3 days and be frugal with it even then. Google "Afrin rebound" and you will see what I mean.

Now you can use something that is just saline/water...Simply Saline is a brand common in the US...and use it as much as you want and it will help. It helps keep the nasal mucosa well hydrated naturally which helps reduce the swelling naturally.

You might need a full face mask but wait until you get the humidifier and use it. You would be surprised at the number of people who have a deviated septum who do quite well with nasal pillow mask once the nasal mucosa are happier (better hydrated).

Humidity needs vary with the individual. Some people need more...some people need less but since you haven't even had a humidifier to use..it makes sense to see if adding humidified air helps.
Some people can live in the high desert and not use a humidifier and their nasal mucosa are totally happy and some people might live in the middle of a rain forest and their nasal mucosa scream for more moisture.

I found that one nasal mask I tried was problematic due to how it fit on the sides of my nose and cheeks. Just the mask pressing against my face caused my sinuses to totally occlude and make nasal breathing impossible. No amount of other efforts would have helped my situation. Not sure how to determine whether your problems originate from the inside or outside, but worth being in tune to just in case a mask change could help.

I got some seawater nasal spray and some nasonex. the seawater one didn't help much but the nasonex really cleared out my nose and I think it may have helped with the leaks?